No doubt, we’re in the middle of an of another species’ extinction hit the news. And that’s only for the species that we know about. Estimates suggest we’re losing several hundred to tens of thousands of species each year, most of them living in the tropics and never described by science.
But amid this tidal wave of species extinctions, there has been some good news. In practice, scientists declare a species extinct when “there is no reasonable doubt” that it is gone, usually meaning that it hasn’t been seen in at least a decade despite efforts to find it. Scientists tend to be pretty conservative when it comes to calling a species extinct, so you can usually assume that if the experts say a species is gone, it’s gone for good.
Still, proving that a species is extinct is difficult. Theoretically, you’d have to search every possible place where that species could be, and if you didn’t find it, then you would know itwas extinct. So maybe it’s not too surprising that at least once declared extinct have been rediscovered in recent years A few of these stories are almost unbelievable:
The short-tailed albatross was formerly abundant in the western Pacific Ocean but was decimated on its nesting grounds by hunting and plume gathering (bird feathers were once popular as fashion accessories). By the 1930’s only a few birds were left nesting on the Japanese Island of Torishima. Then a double-whammy of military activity and an eruption of the island’s active volcano wiped out the remaining birds. Ornithologists who visited the island in 1949 reported the birds extinct. In 1951 a metereologist on the island reported seeing around 10 “big white birds.” Amazingly, a few young albatrosses had survived at sea. Albatrosses don’t breed until they are several years old, and these birds had avoided the fate that birds on the island met. With protection from the Japanese government, that tiny population has since grown to well over 1,000 birds.
The snail darter is infamous as the fish that almost stopped a dam. A tiny, snail-eating fish of southeastern rivers, by the 1970’s the darter was found only on a stretch of the Little Tennessee River The Tennessee Valley Authority wanted to build a dam on the river that would have flooded the darter’s only habitat. After a supreme court case, a decision by the “God Squad” (the cabinet-level committee which makes final decisions about Endangered Species Act cases), and a rider on an appropriations bill, the dam gates were closed in 1979, and the snail darters were wiped out. In 1980 new darter populations were found in tributaries of the river. The species survives to this day, though it remains threatened.
Even insects have been rediscovered! The Lord Howe Island phasmid is a cigar-sized walking-stick that lived only on an isolated island near Australia. The phasmids, with little experience with predators, fell prey to introduced rats and were wiped by 1920. In 2001, researchers found a population of phasmids on a tiny islet 14 miles away from Lord Howe Island. There were just 20 individuals there, all living on a single shrub. Since then scientists have begun a captive breeding program for the phasmids and are hoping to reintroduce them to Lord Howe Island.
A number of other extinct species have been refound, including almost every kind of animal and some plants A few dedicated people are searching for other species that may still survive (see Scott Weidensaul’s book The Ghost with Trembling Wings for several examples).
Rediscovering any “extinct” species is a cause for celebration, but these rediscovered species are often found at perilously low numbers and in desprate need of help to raise their populations. There is reason for hope, though. Many species have recovered from miniscule numbers. At its low point the New Zeland black robin was down to just 5 individuals. The whooping crane, 19. The Mauritius kestrel fewer than 6. All three populations have since increased to more secure numbers, but only with a lot of hands-on management. Once we’ve rediscovered a lost species, the work has just begun. But returning these species to healthy populations is possible
Biologists will tell you that once a species declines to a certain numer, say 50, it’s doomed. When species hit such low numbers, they can succumb to all sorts of threats from bad weather to disease, and they won’t have the numbers to recover. But the overwhelming lesson from these rediscoveries is that life is resilient. If you give species habitat and some protection, they can hang on, even in the face of overwhelming odds. With the onslaught of bad news about the environment lately, I cling to these little glimmers of hope.